Needle insertion systems and methods

ABSTRACT

Embodiments of a needle insertion system and method are disclosed. One method embodiment includes transmitting a sound beam along an axis to contact a blood vessel; receiving the reflected sound beam from the blood vessel; processing the reflected sound beam to detect the location of the blood vessel; and, responsive to the detection, receiving a needle in a guideway that is oriented parallel to the axis.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.10/897,663 filed Jul. 22, 2004 and entitled, “Needle Insertion Systemsand Methods,” which claims the priority benefit of U.S. ProvisionalApplication No. 60/489,125 entitled, “A Device For Locating Veins andAligning and Inserting Intravenous Catheters and Blood Drawing NeedlesTherein,” filed Jul. 22, 2003, each of which is entirely incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure is generally related to the medical field, and,more particularly, is related to systems and methods for locating veinsand other blood vessels and inserting needles and catheters therein.

BACKGROUND

In the medical field, a common procedure performed by emergency medicaltechnicians, phlebotimists, nurses, doctors, and other medical fieldpersonnel is locating veins and inserting intravenous (IV) tubes (e.g.,catheters) and blood drawing needles therein. One problem that is oftenencountered when administrating an IV or drawing blood is that it isoften difficult for the medical person to locate a vein. This problem isparticularly pronounced with obese or pediatric patients, or whenconditions are less than favorable, for example on a battlefield or atan accident scene. Various methods and devices have been devised to helpa user to locate a vein that would be otherwise difficult to locate.

One popular method for locating a vein is the Doppler sonar method. Inthis method, a transmitter (or transceiver) provides a high frequencysound signal that is transmitted through the surface of a patient's skinin an effort to locate a vein. Although sound will be scattered by alltissues, for the blood flowing through a vein, the signal will beDoppler shifted due to the motion of the blood. If the velocity of theblood is v, the received signal (received at the transducer of atransceiver or receiver) is shifted in frequency as provided in Equation1 below:

$\begin{matrix}{{\Delta \; f} = {2f\frac{v}{c}\cos \; \theta}} & {{Eq}.\mspace{14mu} 1}\end{matrix}$

where f is the transmitted frequency (e.g., 10 Mega-Hertz (MHz)), c isthe speed of sound in the tissue (approximately 1500 meters per second(m/sec)) and θ is the angle between the flow velocity direction and thesound beam axis. For a typical vein, the flow velocity is of the orderof 10 cm/sec. If θ is, for example, 30°, the frequency shift will be 667Hz. Such shifts can be detected by “beating” the received signal againstthe transmitted signal. The presence of an audio frequency beat signalin the output (in this case at 667 Hz) indicates a Doppler shift, andhence that the beam is intersecting a blood vessel such as an artery orvein. Since arterial flow is away from the heart and venous flow istowards the heart, the distinction between arteries and veins is made bydetermining whether the Doppler shift is positive or negative. Both thesize of the Doppler shift and the strength of the Doppler shiftedsignals are helpful in selecting the most suitable vein since a largervein has higher flow velocities in addition to being a better scatterer.

Although the technology used to locate a vein has improved, the methodsused to insert a needle quickly and accurately using a hand-held deviceand at a moderate cost could benefit from further development.

SUMMARY

Preferred embodiments of needle insertion systems and methods aredisclosed. One method embodiment, among others, can be generallydescribed by the following steps: transmitting a sound beam along anaxis to contact a blood vessel; receiving the reflected sound beam fromthe blood vessel; processing the reflected sound beam to detect thelocation of the blood vessel; and, responsive to the detection,receiving a needle in a guideway that is oriented parallel to the axis.

Another embodiment of a needle insertion method, among others, cangenerally be described by the following steps: transmitting a sound beamalong a first axis to contact a blood vessel; receiving a reflectedsound beam reflected from the blood vessel along the first axis;processing the reflected sound beam to detect the location of the bloodvessel; and, responsive to the detection, receiving a needle in aguideway that is oriented along a second axis that enables the needle tointersect the first axis in proximity to the blood vessel.

A needle insertion system embodiment, among others, can include atransducer assembly configured to radiate a sound beam along a firstaxis and detect a blood vessel responsive to receiving a reflected soundbeam; and a coupler that is configured to reflect the sound beam along asecond axis to and from the blood vessel, the coupler configured with aguideway that is oriented parallel to the second axis.

Another needle insertion system, among others, can include a transducerassembly configured to radiate a sound beam along a first axis anddetect a blood vessel responsive to receiving a reflected sound beam;and a coupler that is configured to reflect the sound beam along asecond axis to and from the blood vessel, the coupler configured with aguideway that is oriented along a third axis that enables the needle tointersect the second axis in proximity to the blood vessel.

The preferred embodiments also include a coupler that acts as aninterface between a needle and a skin surface through which the needleis to advance to contact a blood vessel. In one embodiment, amongothers, a coupler can include means for receiving a reflected sound beamalong a first axis; and means for receiving a needle along an axis thatis parallel to the first axis.

Another embodiment of a coupler, among others, can include means forreflecting a transmitted sound beam along a first axis and a reflectedsound beam reflected from a blood vessel along the first axis; and meansfor receiving a needle along a second axis that is oriented to enablethe needle to intersect the first axis in proximity to a blood vessel inwhich the needle is to be inserted.

Other systems, methods, features, and advantages of the disclosure willbe or become apparent to one with skill in the art upon examination ofthe following drawings and detailed description. It is intended that allsuch additional systems, methods, features, and advantages be includedwithin this description, and be within the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily to scale, emphasisinstead being placed upon clearly illustrating the principles of thedisclosed systems and methods. Moreover, in the drawings, like referencenumerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic diagram that illustrates an embodiment of a needleinsertion system.

FIG. 2 is a block diagram that illustrates an embodiment of a transducerassembly of the needle insertion system shown in FIG. 1.

FIG. 3 is a side-view cut-away that illustrates an embodiment of acoupler of the needle insertion system shown in FIG. 1.

FIG. 4 is a schematic diagram of a coupler embodiment similar to thatshown in FIG. 3 that illustrates application of a sound beam andreceiving a needle along an axis that is parallel to and offset from asound beam axis.

FIG. 5 is a schematic diagram of another coupler embodiment similar tothat shown in FIG. 3 that illustrates application of a sound beam andreceiving a needle along an axis that has a depth dependent offsetrelative to a sound beam axis.

FIG. 6 is a front-view schematic diagram of the needle insertion systemshown in FIG. 1 that illustrates traversing the skin surface to obtain astrong signal that indicates location of a suitable vein and insertionlocation along the vein.

FIG. 7A is a schematic diagram that illustrates an embodiment of aneedle insertion system.

FIG. 7B is a side-view cut-away of an embodiment of a coupler of theneedle insertion system shown in FIG. 7A.

FIG. 8 is a flow diagram that illustrates one needle insertion methodembodiment corresponding to the embodiment shown in FIG. 4.

FIG. 9 is a flow diagram that illustrates one needle insertion methodembodiment corresponding to the embodiment shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Disclosed herein are various embodiments of a needle insertion systemand method. A needle insertion system assists a user (e.g., a skilledmedical professional such as a nurse, or an unskilled person fordo-it-yourself medical kits) in locating a vein, for example, or artery,and inserting an intravenous (IV) tube, catheter, and/or blood drawingneedle therein. In one embodiment, a needle insertion system isdisclosed as comprising a handheld device having a transducer assemblyand a coupler. The transducer assembly includes a focused ultrasonictransducer that produces a narrow sound beam with a focal region (e.g.,the focal region in one embodiment having a diameter of less than orequal to approximately 1 millimeter (mm), approximately 2.5 centimeters(cm) in length, and whose center is approximately located 5 cm from thetransducer face). The sound beam is preferably generated as a pulsedbeam having a frequency of approximately 10 Mega-Hertz (MHz). Thetransducer, operating in one embodiment in a transmit/receive mode,detects a vein by functioning as a pulsed Doppler blood flow detector.

The coupler is configured to guide or direct a needle into a veinquickly and easily, and, preferably, to detach from the needle quicklyand easily. In principle, the coupler portion works by aligning the axisof a needle relative to the axis of the sound beam radiated from thetransducer assembly. If the beam is known to intersect a vein (usingDoppler sonar), then advancing the needle in a path provided integral toor adjacent to the coupler along the beam axis, parallel to the beamaxis at a slight offset, or offset in a depth dependent manner tointersect the beam axis, results in the needle entering the vein.

Although described in the context of locating a vein and inserting aneedle therein, it would be understood by those having ordinary skill inthe art that the principles disclosed in this disclosure can also applyto the location of other blood-carrying vessels. Further, althoughdescribed using a needle, similar principles apply to the insertion ofother objects such as a catheter, tube, or shunt, and thus areconsidered to be within the scope of the preferred embodiments.

In the description that follows, a needle insertion system embodiment isdescribed in FIG. 1, and the various components that comprise the sameis described with respect to FIGS. 2-4. An additional embodiment of acoupler for the needle insertion system described in FIG. 1 isillustrated in FIG. 5. FIG. 6 illustrates a method to elicit an optimalfeedback signal indicating whether or when the center of a vein has beenlocated. FIGS. 7A and 7B illustrate another embodiment of a needleinsertion system and its corresponding components. Finally, FIGS. 8 and9 illustrates various needle insertion method embodiments.

FIG. 1 is a schematic diagram that illustrates an embodiment of a needleinsertion system. The needle insertion system 100 includes a coupler 102and a transducer assembly 104. The coupler 102 includes a guideway 108,in which a needle 110 can be inserted and advanced along the guideway108 and through the skin surface 112 to puncture a vein 114 located in abody 106 (for blood drawing and catheter insertion, the body site ofinterest will often be an arm, but the needle insertion system can beused in other locations of the body). Although the guideway 108 can beconfigured as a channel that runs through the body of the coupler 102,preferably the guideway 108 is configured as a channel that runs alongthe bottom, preferably angled surface of the coupler 102. The transducerassembly 104 can be rotatably attached and detached from the coupler102, and/or slidably detached and re-attached in other embodimentsaccording to well-known attachment/detachment mechanisms. Still in otherembodiments, the transducer assembly 104 and the coupler 102 can befixably attached or the two components can be molded as a singlecomponent. The needle 110 can be packaged with the coupler 102, forexample disposed in the guideway 108 as part of the entire coupler 102,or available separately from the coupler 102.

FIG. 2 is a block diagram that illustrates an embodiment of a transducerassembly 104 of the needle insertion system 100 shown in FIG. 1. Thetransducer assembly 104 includes a transducer module 202, a switchmodule 204, a transmitter module 206, a receiver module 208, anoscillator and processing module 210, and an output module 212. One ormore of the modules can be configured in hardware, software, or acombination of hardware and software. The transducer assembly 104 can bebattery powered (not shown) and/or powered externally through use of acord or other mechanism for connecting to an external power source.

The transducer module 202 preferably radiates a pulsed Doppler soundfield which, in one embodiment, focuses to a beam of approximately 1 mmin diameter over a length of approximately 2.5 cm, as generated from thetransmit electronics described below. The 1 mm diameter sound beam issmaller or comparable in diameter to a vein from which it is suitable todraw blood. The transducer module 202 includes a transducer element (notshown) that can be configured to radiate beams of greater or smallerdiameter depending on the application, by adjusting the frequency. Thetransducer module 202 is also configured to receive a reflected soundbeam, which it converts to a signal(s) for processing by the receiveelectronics described below.

The oscillator and processing module 210, in cooperation with thetransmitter module 206, generate the pulses at a frequency ofapproximately 10 MHz, although sound beams of other frequencies can begenerated depending on the application. The pulsed mode is preferablyimplemented in both transmit and receive modes. The receiver module 208includes receive and processing electronics to receive the reflectedsignal and determine the presence or absence of a Doppler shift. If aDoppler shift is detected, an audible sound, tactile sensation (e.g.,vibration), and/or visual display is activated via the output module212. For example, an audible sound may be activated and may beadjustable based on the surrounding environment (e.g., loud enough tohear over sirens, etc.). As another example, a graphics user interfacemay be presented on the package of the transducer assembly 104 and whichmay show an arrow(s) indicating the direction of movement a user needsto take along a person's body to locate a vein or to optimize the signalstrength (and thus center the needle on the vein). The switch module 204provides functionality for switching between receive and transmitfunctionality. Note that the use of pulsed Doppler may also enableestimation of the depth of the vein from the pulse transit time.Further, the electronics of the transducer assembly 104 are well knownto those having ordinary skill in the art, and thus further explanationof each component will be omitted for brevity.

The transducer assembly 104, when detachable from the coupler 102, doesnot have to be sterilizable. As a corollary to the detachable/attachablefeature, the transducer assembly 104 is reusable with a plurality ofdifferent couplers 102.

Note that in some embodiments, two transducers may be used (a transmitand receive transducer) and the switch omitted.

FIG. 3 is a side-view cut-away that illustrates an embodiment of acoupler of the needle insertion system 100 shown in FIG. 1. The coupler102 comprises a coupling portion 302 and a reflective portion 304. Inone embodiment, the coupler 102 may be disposable, and included with theneedle 110 in a plastic package (not shown) designed to maintain thesterility of the coupler 102 and the needle 110. The coupling portion302 is preferably made of a plastic material, although other materialsmay be used. The coupling portion 302 comprises a chamber 306 that ispreferably cylindrical in configuration. The chamber 306 contains acoupling material (not shown). The coupling material may include water,ultrasonic gel, solid rubber couplant, among other coupling materialsuitable for propagating the sound beam. The coupling portion 302 alsoincludes a window 308 which allows the transmitted sound beam to radiateinto the body 106 (FIG. 1) and allows the reflected sound beam toradiate back into the coupling portion 302. The window 308 may becomprised of a thin (e.g., approximately 25 microns to 250 micronsthick) plastic material. The coupling portion 302 further includes ahousing portion 310, which receives a transducer element (not shown) ofthe transducer module 202 (FIG. 2) when the coupling portion 302 isattached to the transducer assembly 104. The coupling portion alsoinclude a tube 312. The tube 312 serves as a conduit to enable fillingthe coupler with a coupling material, such as water. In someimplementations, an ultrasonic coupling gel (not shown) may be appliedto the outside surface of the coupler 102 (i.e., the surface contactingthe skin surface 112).

The reflective portion 304 is attached to the coupling portion 302, forexample using an adhesive, through the use of screws, or other fasteningmechanisms known to those having ordinary skill in the art. Thereflective portion 304 preferably has a flat reflecting surface(reflecting the sound beam) and is preferably comprised of a metallicmaterial, such as stainless steel, although other reflective material,or a combination of reflective and non-reflective material, may be used.The reflective portion 304 redirects the sound beam received from atransducer element, or the reflected sound beam received from thelocated vein, at a defined angle. The reflective portion includes aguideway 108 that has a defined angle with respect to the skin surface112 (FIG. 1), and is used to guide a needle along a predeterminedorientation. In one embodiment, the guideway 108 is configured toprovide a predetermined offset between the sound beam and the needle.The offset can be made depth-dependent or depth-independent by modifyingthe attachment angle (i.e., the angle between the guideway 108 and thehorizontal surface of the coupler 102, such as β in FIG. 4 describedbelow) with respect to the skin surface 112.

In one embodiment, the guideway 108 is made of a short, flexible tubeattached to (adjacent) the reflective portion 304 (e.g., running alongthe bottom, angled surface of the reflective portion 304). The guideway108 is preferably made of a plastic material, and can be attached usingan adhesive or other fastening mechanisms known to those having ordinaryskill in the art. A slot (not shown) is provided at the bottom of theguideway 108 running along the length of the guideway to enable a userto disengage the coupler 102 from a needle once the vein is punctured.In some embodiments, the slot can be omitted and the coupler 102 can bedisengaged from the needle by cutting the guideway 108. In someembodiments, the slot can be omitted based on applications wheredisengagement from the needle is not needed. The guideway 108 has adiameter that is large enough to allow the needle to be advanced throughit, yet small enough to hold the needle firmly. In some embodiment, aguideway of similar features can be configured as a channel bored withinthe body of the reflective portion 304.

FIG. 4 is a schematic diagram of a coupler embodiment, coupler 102 a,similar to that shown in FIG. 3, and that illustrates application of asound beam and receiving a needle along an axis that is parallel to andoffset from a sound beam axis. As shown, a transducer element 402 of thetransducer assembly 104 (FIG. 1) is disposed conformably (although anywell-known attachment/detachment mechanisms may be employed) in thehousing portion 310 and secured enough to assure proper alignmentbetween the transducer assembly 104 and the coupler 102 a. In oneembodiment, the transducer element 402 has a concave surface 404 toprovide a focused sound beam. The focused beam could also be achievedusing an acoustic lens. The transducer element 402 is disposed at adistance (represented by the line labeled “A” in FIG. 4) ofapproximately 4 cm from the location 406 on the reflective surface onwhich a sound beam 408 (shown herein as the centerline of the beam, withthe understanding that a larger sound profile is preferably radiated)impinges to the point on the convex surface 404 farthest from saidlocation 406. This 4 cm distance enables a 1 mm diameter sound beamfocal region to begin at the skin surface. Note that this dimension “A”may vary in some embodiments, depending on the characteristics of thesound beam from the focused transducer element 402. “A” can bedetermined mathematically according to known formulas, and/or determined(or verified) experimentally. Thus, the transducer element 402 isdisposed in the housing portion 310 at a suitable distance toaccommodate a focal length of approximately 5 cm, in such a way that thefocal region begins at the surface of the skin 112, which enablesdetection of a vein along a longer range. For example, experimentationand mathematical analysis have indicated that the focal region for asound field produced by a 1 centimeter (cm) diameter, 10 MHz transducerwith a focal length of 5 cm is ellipsoidal, about 1 mm in diameter, andmore than 2 cm long. In other words, there exists a “beam-like” qualityof the sound field within ±1 cm of the focal point.

The sound beam 408 is radiated in the chamber 306 along an axis that iscoincident with a first axis 410. The chamber 306 includes a couplingmaterial (not shown) that provides an appropriate low loss impedancematched propagation medium for the sound beam 408 when entering theinterior of the body 106 and returning from the interior of the body106.

The sound beam 408 impinges on the reflective portion 304 a at location406 and is reflected along an axis coincident with a second axis 412. Inone embodiment, the angle α between the reflected sound beam along thesecond axis 412 and the skin surface 112 is approximately 30°, althoughother angles may be used. The reflected sound beam 408 is transmittedthrough the skin surface 112 and impinges on the vein 114, and then atleast a portion of the beam is reflected back to the transducer element402 along the second axis 412, and then the first axis 410 afterreflection at 406 of the reflective portion 304 a. The transducerelement 402 converts the received sound beam 408 to an electronic signalthat is processed in the receive electronics (e.g., 208, 210 of FIG. 2)of the transducer assembly 104 to elicit a feedback response by theoutput module 212 (FIG. 2). A feedback response provides an indicationthat a vein has been located, and in some embodiments, an indication ofthe signal strength corresponding to whether the vein has been locatedat a position offset from the centerline of the vein (where blood flowmay be slower) or at the centerline (where blood flow is greatest).

If the vein 114 is located and the signal strength indicates that thelocation corresponds to an optimal position for insertion of the needle110, then the user can insert the needle 110 through the guideway 108.The guideway 108 is oriented parallel to the second axis 412, offset afixed and constant distance (e.g., 0 to 5 mm) from the second axis 412.By remaining offset from the second axis 412, the inserted needle 110interferes minimally with the sound field present beneath the skinsurface 112, and enables the user to continually monitor the location ofthe vein 114 as the needle is advanced, up until the time correspondingto when the vein 114 is punctured. In one embodiment, the angle β whichis the angle formed between the guideway 108 and the skin surface 112,is approximately 30°, although other angles may be used.

FIG. 5 is a schematic diagram of another coupler embodiment, coupler 102b, that illustrates application of the sound beam 408 and receiving theneedle 110 along an axis 502 that has a depth dependent offset relativeto a sound beam axis 412. As shown, the coupler 102 b has similarcomponents to those found in couplers 102, 102 a of FIGS. 3 and 4,respectively, and thus discussion of the same will be omitted orabbreviated. The sound beam 408 is radiated from the transducer element402 along the first axis 410, reflected off a reflective portion 304 b,and provided along the second axis 412 to impinge on the vein 114. Theangle α is approximately 30°, although other angles may be used. Theguideway 108 (and also the bottom surface of the reflective portion 304b in one embodiment) form an angle β of approximately 23°, althoughother angles may be used. Thus, the needle 110 is advanced along theguideway 108 along a third axis 502, resulting in the needle 110intersecting the sound beam 408 provided along the second axis 412 in alocation proximally (i.e., the axis 502 intersecting axis 402 in alocation approximately at the point where the focal region ends, such aswhere the beam width ceases to be 1 mm in diameter in embodimentsdescribed herein) to the vein 114. Note that the offset will vary basedon the depth of the vein 114.

FIG. 6 is a front-view schematic diagram of the needle insertion system100 shown in FIG. 1 that illustrates traversing the skin surface 112 toobtain a strong signal indicating location of the vein 114 and/oroptimal locations along the vein 114. For example, the needle insertionsystem 100 is shown traversing across the skin surface, but it also istraversable in the direction running along the length of the body 106,as well as rotatably traversable. In one implementation, the needleinsertion system 100 is moved (represented by the double-arrow headabove the system 100) across the skin surface 112 until the vein 114 isdetected. Vein detection (and/or location) may be indicated by a light,sound or other display or feedback, as described above. The sound beamreflection from the vein 114 enables the needle 110 (or an IV catheter,for example, in some implementations) to be aligned, but offset, withthe sound beam 408. In other words, the sound beam 408 is known (usingDoppler technology) to be passing through a suitable vein 114. Theneedle is advanced through the guideway 108 a (parallel to, but offsetfrom the sound beam 408 in this implementation), passing through theskin surface 112 and advanced until it punctures the vein 114. The usercontinually receives feedback that he or she is advancing the needle 110in the right direction until the vein 114 is punctured.

FIG. 7A is a schematic diagram that illustrates another embodiment of aneedle insertion system 700. The needle insertion system 700 differsfrom the prior described embodiments in that a needle is advanced to avein along an axis that is coincident with the sound beam. The needleinsertion system 700 includes a transducer assembly 704 attached to thecoupler 702. Preferably, the transducer 704 is attachable and detachablefrom the coupler 702 (e.g., shown here as rotatably attachable anddetachable). The transducer assembly 704 includes the same or similarelectronics to the transducer assembly 104 shown in FIG. 2, and thusillustration and discussion of the same is omitted.

FIG. 7B is a side-view cut-away of an embodiment of the coupler 702 ofthe needle insertion system 700 shown in FIG. 7A. With continuedreference to FIG. 7A, the coupler 702 is preferably made of plastic, andcomprises membranes 706 and 708 and a chamber 710 that includes anultrasonic coupling material (not shown). Membranes 706 and 708 may bemade of, for example, rubber. The coupling material can be, for example,a sterile, de-aerated saline. In one embodiment, the coupler 702 may bedisposable, and included with the needle 110 in a plastic package (notshown) designed to maintain the sterility of the coupler 702 and theneedle 110. For IV catherization implementations, the coupler 702 can bedesigned to split in half to allow removal of the coupler 702 after thevein 110 has been punctured, an unnecessary step for simply drawingblood. The membranes 706 and 708 are traversed by the needle 110 duringthe insertion, the needle 110 being advanced through the guideway 712.The membrane 706 is also an ultrasound reflector. In one embodiment, themembrane 706 is air-backed and preferably as smooth and flat aspossible. The membrane 708 serves to couple the sound beam 408 into thetissue of the body 106. In some implementations, an ultrasonic couplinggel (not shown) may be applied to the outside surface of the membrane708 (i.e., the surface contacting the skin surface 112).

Directing attention to FIG. 7A, the operation of the transducer system700 will now be described. The transducer element 402 of the transducerassembly 704 radiates the sound beam 408 a distance (represented by theline labeled “B”) of approximately 4 cm to the membrane 706 in similarmanner to that described in association with FIG. 4. The sound beam isradiated along a first axis 410. The sound beam 408 is reflected by theair-backed membrane 706 before entering the body 106 through themembrane 708. The reflected sound beam 408 travels along the second axis412. The travel path and orientation of the reflected sound beam 408enables the needle 110 (or an IV catheter) to be exactly aligned orsubstantially aligned with the reflected sound beam 408, which is knownby Doppler to be passing through a suitable vein 114. Although the soundbeam 408 is shown to make an angle α of 30° relative to the plane of theskin surface 112, it would be understood by one having ordinary skill inthe art that some embodiments may utilize one of a variety of differentangles (e.g., 45° or 20° depending on the application.

The needle 110 is advanced (not shown) through the guideway 712, whichis coincident (or coaxial) with the sound beam 408. The needle 110 isadvanced through the membrane 706, through the chamber 710 (and thusthrough a coupling material not shown, such as saline fluid), and thenthrough the membrane 708, and continually (still along the second axis412) advanced until the needle 110 punctures the vein 114. The coaxialalignment of the guideway 712 and sound beam assures (or assures with ahigh-probability of certainty) that the needle 110 will encounter thevein 114. The coupler 702, in one embodiment, can then be easilydisassembled into two or more pieces and removed, and the IVcauterization or blood draw can be completed.

In some embodiments, the saline filled chamber 710 can be replaced witha solid insert (not shown), which can be removed after the vein 114 isdetected to allow passage of the needle 110. In such embodiments, themembranes 706 and 708 may be omitted and the user can view the insertionpoint.

In view of the above description, it will be appreciated that oneembodiment of a needle insertion method 800 may comprise, as illustratedin FIG. 8, transmitting a sound beam along an axis to contact a bloodvessel (802); receiving the reflected sound beam from the blood vessel(804); processing the reflected sound beam to detect the location of theblood vessel (806); and, responsive to the detection, receiving a needlein a guideway that is oriented parallel to the axis (808).

Another embodiment of a needle insertion method 900 may comprise, asillustrated in FIG. 9, transmitting a sound beam along a first axis tocontact a blood vessel (902); receiving a reflected sound beam reflectedfrom the blood vessel along the first axis (904); processing thereflected sound beam to detect the location of the blood vessel (906);and, responsive to the detection, receiving a needle in a guideway thatis oriented along a second axis that enables the needle to intersect thefirst axis in proximity to the blood vessel (908).

Any process descriptions or blocks in the flow diagrams of FIGS. 8 and 9should be understood as representing steps in an embodiment of onemethod, and alternate implementations are included within the scope ofthe preferred embodiments, as would be understood by those reasonablyskilled in the art.

It should be emphasized that the above-described embodiments,particularly, any “preferred” embodiments, are merely possible examplesof implementations, and are merely set forth for a clear understandingof the principles of the disclosure. Many variations and modificationsmay be made to the above-described embodiment(s) without departingsubstantially from the spirit and principles of the disclosure. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure.

1. A needle insertion method, comprising: transmitting a sound beamalong an axis to contact a blood vessel; receiving the reflected soundbeam from the blood vessel; processing the reflected sound beam todetect the location of the blood vessel; and responsive to thedetection, receiving a needle in a guideway that is oriented parallel tothe axis, wherein receiving a needle in a guideway that is orientedparallel to the axis includes receiving the needle in the guideway thatis oriented coincident with the axis.
 2. A needle insertion method,comprising: transmitting a sound beam along a first axis to contact ablood vessel; receiving a reflected sound beam reflected from the bloodvessel along the first axis; processing the reflected sound beam todetect the location of the blood vessel; and responsive to thedetection, receiving a needle in a guideway that is oriented along asecond axis that enables the needle to intersect the first axis inproximity to the blood vessel.
 3. The method of claim 2, whereintransmitting includes transmitting a pulsed ultrasonic beam focusedwithin the body to a diameter of approximately 1 millimeter.
 4. Themethod of claim 2, further including providing feedback to a user inresponse to the detection.
 5. The method of claim 4, wherein providingfeedback includes providing the feedback at least until the needlecontacts the blood vessel.
 6. The method of claim 2, further includingproviding at least one of an audible sound, a visual display signal, anda tactile signal to a user in response to the detection.
 7. The methodof claim 2, wherein receiving a needle in a guideway includes receivingthe needle along the second axis that has a depth-dependent offsetrelative to the first axis.
 8. The method of claim 2, wherein receivinga needle in a guideway further includes contacting the blood vessel withthe needle proximally to where the sound beam was reflected from theblood vessel.
 9. A needle insertion system, comprising: a transducerassembly configured to radiate a sound beam along a first axis anddetect a blood vessel responsive to receiving a reflected sound beam;and a coupler that is configured to reflect the sound beam along asecond axis to and from the blood vessel, the coupler configured with aguideway that is oriented parallel to the second axis, wherein theguideway is oriented coincidentally with the second axis.
 10. A needleinsertion system, comprising: a transducer assembly configured toradiate a sound beam along a first axis and detect a blood vesselresponsive to receiving a reflected sound beam; and a coupler that isconfigured to reflect the sound beam along a second axis to and from theblood vessel, the coupler configured with a guideway that is orientedalong a third axis that enables the needle to intersect the second axisin proximity to the blood vessel.
 11. The system of claim 10, whereinthe transducer assembly includes a transducer set back a defineddistance from a skin surface on which the coupler rests, the transducerconfigured to radiate a pulsed ultrasonic beam focused within the bodyto approximately 1 mm in diameter.
 12. The system of claim 10, whereinthe transducer assembly includes an output module that is configured toprovide at least one of an audible sound, a visual display signal, and atactile signal to a user in response to the detection of the bloodvessel.
 13. The system of claim 10, wherein the guideway is configuredto receive the needle along the third axis that has a depth dependentoffset relative to the second axis.
 14. The system of claim 10, whereinthe guideway is receptive to a needle that can be advanced in adirection oriented along the third axis to contact the blood vessel in alocation that is proximal to where the sound beam intersects the thirdaxis.
 15. The system of claim 10, wherein the transducer assemblyincludes at least one of a switch, transmitter electronics, receiverelectronics, an oscillator, a power amplifier, a pulse generator, and aprocessor.
 16. The system of claim 10, wherein the coupler includes achamber that contains a coupling material.
 17. The system of claim 10,wherein the coupler includes a reflective portion that reflects thesound beam from the transducer assembly through a window to the bloodvessel, and from the blood vessel through the window to the transducerportion.
 18. The system of claim 10, wherein the coupler is at least oneof attachable and detachable from the transducer assembly.
 19. Thesystem of claim 10, wherein the coupler is capable of disassembly. 20.The system of claim 10, wherein the guideway is configured with a slotthat enables separation of the coupler and the needle.
 21. A couplerthat acts as an interface between a needle and a skin surface throughwhich the needle is to advance to contact a blood vessel, the couplercomprising: means for receiving a reflected sound beam along a firstaxis; and means for receiving a needle along an axis that is parallel tothe first axis, wherein the means for receiving a needle is orientedcoincidentally with the first axis.
 22. A coupler that acts as aninterface between a needle and a skin surface through which the needleis to advance to contact a blood vessel, the coupler comprising: meansfor reflecting a transmitted sound beam along a first axis and areflected sound beam reflected from a blood vessel along the first axis;and means for receiving a needle along a second axis that is oriented toenable the needle to intersect the first axis in proximity to a bloodvessel in which the needle is to be inserted.
 23. The coupler of claim22, wherein the means for receiving a needle is a guideway.
 24. Thecoupler of claim 23, wherein the guideway is slotted.
 25. The coupler ofclaim 22, wherein the means for receiving a reflected sound beamincludes means for receiving a transmitted sound beam along a thirdaxis.
 26. The coupler of claim 25, wherein the means for receiving areflected sound beam includes a chamber configured to contain a couplingmaterial, a reflective portion, a window, and a transducer assemblyattachment means.